Automatic additional-air valve for combustion-engines



A. E. PEPPERCORN.

AUTOMATIC ADDITIONAL AIR VALVE FOR COMBUSTION ENGINES.

APPLICATIONIFILED JULY 29. 191a.

1,343,375. v P atnted June 15, 1920.

A 5. Peppercorn UNITED ALFRED EDWARD PEPPERCORN, OF FORBES, NEW SOUTH WALES, AUSTRALIA.

AUTOMATIC ADDITIONAL-AIR VALVE FOR COMBUSTION-ENGINES.

Application filed m 29,

This invention relates to that type of automatic additional air valve for combustion engines in which a cylinder, one end of which is open to atmosphere, and the other end of which is in communication with the inlet manifold of the engine, is fitted with a spring pressed piston, and said piston, when moved against said spring responsively to variations in the subatmospheric pressure in the manlfold, opens an air admission vent through which additional air enters to the manifold, diluting therein the fuel mixture which has been inducted. from a carbureter or a mixing valve.

To obtain the necessary exactness of control and a graduated admission of air into the manifold proportionate to the degree of depression therein during running, the control piston, the movement of which is responsive to variations in the degree of subatmospheric pressure in the manifold, should be of considerable area, should be always subject to full atmospheric pressure of the induction on its inner face, and to obtain uniform regulation of its movement by means of a loading spring it should have a long stroke.

The air admission valve should be of relatively small. dimensions and of a type which permits of delicate setting and adjustment. Such an air valve having its movements controlled by such a piston will then be automatically opened and closed proportionately to the pressure changes in the manifold without dithering and will be automatically fully opened,

' to admit a full flow of air for braking purposes when the throttle valve is fully closed so as to prevent entrance of air or fuel mixture to the manifold viathe carbureter 50 or the mixing valve.

An additional air valve according to my I invention is illustrated in the accompanying drawing, in which Figure 1 is a longitudinal sectional elevation, in which the valve is shown closed: Fig. 2 is a partial longitudinal sectional elevation, in which the Specification of Letters Patent. Patented June 15, 1920.

1918. Serial No. 247,190.

valve is shown in the full open position; Fig. 3 is a side elevation with a fragment broken away to show the valve seat; Fig. 4 is a semi-diagrammatic view illustrating the mounting of the valve on the induction manifold of an automobile engine; and Fig.

the smaller diameter bore 11, but may be I very much larger. A piston 12, preferably tion with the front end of the large bore chamber 10. At its front end the fitting is closed by a nipple piece 16, which is adapted to be screwed into a tapped hole in, the engine manifold between the carbureter or mixing valve and the cylinder inlet valves, as for instance as indicated in Fig. 4, so thatthe front end of the chamber 10. is placed in communication with the engine manifold. The extreme rear end .of the casing terminates in a screwed stud 18; this stud may be integral with it, or it may be separate and screwed into it. The stud 18 serves to carry a yoke 19 which may be set wherever required by means of two jam 11 is ported at either side. The slot portions'23 of these ports extend through the middle length of the chamber 11, and rearwardly they are extended as narrow taper slits 24, the ends of which terminate a little forward of-the rear end of the chamber 11, so that the plunger does not commence to uncover them until it has moved a short distance off the valve seat 25. At the base, the bore of the chamber 11 is finished to a conical valve seating '25, and the end of the plunger 14 is turned conical andground to the face 25, so as to form a tight closure nuts 20 and 21. The narrow bore chamber therewith when the valve is in the closed position shown in Fig. 1. 'When the-valve is so closed, air cannot pass from atmosphere through the ports 23, '24 and the tubular passage 15 to the manifold. A bar yoke 26 is passed through a close fitting hole drilled through the plunger 14, and said yoke extends through the lateral ports 23, and carries on its ends the ends of two helical loading springs 28; the other ends of these springs are attached to the arms of the adjustable yoke 19. The tension of the piston loading springs 28 is set by adjusting the nuts 20 and 21 on the stud 18. 29 are air holes through the casing wall, behind the rear end of the piston 12, to allow free ingress of air to the annularspace in the chamber 10 rearward of the piston when the piston moves forwardly responsive to variations in subatmospheric pressure in the engine manifold.

The overall length of the fitting may be shortened by omitting the loading spring adjusting yoke 19 and the stud 18 which carries it, also omitting the bar yoke 26, and using in place thereof a helical loading spring 30 in compression set in front of the piston 12, as shown in Fig. 5. the'spring 30 take their abutments respectively against the forward end of the piston 12 and against the back of the nipple cap 16, and the tension of the spring is adjusted by screwing the nipple 16 more or less into the casing 5 the nipple is secured in adjusted position by means of jam nut 32.

In operation, when the engine is idle, the piston loading springs 28, (or 30 as the case may be) are tightened up to hold the valve in the closed position in which it is shown in Fig. 1. Air cannot then pass from atmosphere through the valve. After the engine has been started, the loading spring tension is adjusted so that the induction suction acting on the forward side of the piston 12 permits the superior'pressure of atmosphere to force the piston forward and compress the loading spring, thereby opening the valve at the seat 25. Further forward movement of 'the plunger 14 takes place when the engine is accelerated, and the taper slits 24 in the side of the chamber 11 are then gradually opened, and atmospheric air enters therethrough, passes over the end of the trunk and flows through the tubular passage 15 into the chamber 10 and thence through the nipple 16 to the induction manifold 31. Forward movement of the piston 12 is permitted by free admission of atmospheric air behind it through the air holes 29. As the suction in the manifold increases as the engine is further accelerated, the loading springs 28 (or 30 as the case may be) are flexed proportionately and permit the piston and plunger to move forward gradually further opening up the ports 24, 23. The initial tension on the loading springs must be adjusted so that movement'of thevalve isinsufficient to The ends of sion at which the engine displays a tendency to backfire under load, and they are then tightened slightly, thus insuring a fuel mixture slightly denser than required for certainty of explosion under load.

It will be found in practice that with ap I proximately correct adjustment of the spring loading and appropriate. trimming of the ports 24-23, running air will be I taken through them in sufficient quantity to dilute the engine charge to the desired ex tent unless it is initially abnormally rich.

In the case of a car having the device fitted to its engine, when the car is in motion and the throttle is closed, the depression in the manifold will be in excess of the reac-.-

tion of the loading springs, and the piston and plunger will therefore move forward full stroke, thereby admitting free air through the ports 24 23 and the passage 15 tothe manifold, sothat the-suction de- I 'mand of the cylinders is satisfied and a braking effect is obtained without waste of fuel through the carbureter, and without drawing lubricating oil upinto the cylinder past the piston rings and thereby fouling the cylinders.

What I claim as my invention and desire to secure by Letters Patent is 1. An air admission valve automatically responsive tofluctuations in sub-atmospheric pressure in the manifold of a combustion engine, comprising two coaxial intercommu nicating cylinder chambers of substantially different diameters with an air ventv at the base of the larger chamber and a closed end on the smaller chamber, a piston fitted to said larger chamber, a plunger extension on said piston fitted to said smaller chamber, the piston and plunger havinga tubular passage therethrough, a nipple connection for an. engine manifold on the end of the said larger chamber, a valve face. on the plunger endand a corresponding valve seatthe smaller chamber, a carrier yoke adjust ablymounted thereon,-and a pair of helical,-

springs in tension having-their ends respectively attached to said draw yoke and said carrier yoke.

2. An air admission valve automatically responsive to fluctuations in subatmospheric pressure in the manifold of a combustion engine, comprising a differential bore cylinder with a free air vent to the atmosphere at the base of the larger bore, a piston and a plunger extension of substantially smaller diameter thereon, said piston and plunger being fitted respectively to the two bores of the cylinder, a valve face on the plunger end, a corresponding valve seating adapted to be closed thereby in the end of the small bore of the cylinder, means including a spring and a device for regulating its tension for opposing atmospheric pressure acting behind said piston while a condition of partial vacuum exists in the cylinder bore at the front end thereof, the side of the small bore of the cylinder being provided with air ports adapted to be progressively uncovered by the plunger in its forward motion therein.

3. An automatic air admission valve con prising a cylinder concentrically bored on a large diameter at one end and on a substantially smaller diameter on the other end, with a free air vent intermediate said large and small bores, means for fitting the larger end of said cylinder in communication with the induction manifold of a com bustion engine, a spring loaded piston mov-' bore, the ends of the respective cylinder bores being connected by passages extending through said plunger and piston and spring tension adjusting means, and the side of said smaller cylinder bore having an air admission port adapted to be gradually uncovered by said plunger in its forward movement therein.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ALFRED EDWARD PEPPERC ORN.

Witnesses:

W. J. HUMPHREYS, H. O. CAMPBELL. 

